Lecture "Brute-force argorithms", exercise 5

[essepuntato]

Write in Python the function def my_reversed(input_list), which behave like the built-in function reversed() introduced in Section "Insertion sort" and returns a proper list, and accompany the function with the related test case. It is not possible to use the built-in function reversed() in the implementation.

[ghasempouri1984]

unlike reversed(), with [::-1] code reverse the list without modifying it:

def test_my_reversed(input_list, expected):
    result = my_reversed(input_list)
    if expected == result:
        return True
    else:
        return False


def my_reversed(input_list):
    reversed_list = input_list[::-1]
    return reversed_list


print(test_my_reversed([], []))
print(test_my_reversed([1], [1]))
print(test_my_reversed([1, 2, 3, 4], [4, 3, 2, 1]))
print(test_my_reversed([1, 2, 3, 4, "5", " ", 7], [7, " ", "5", 4, 3, 2, 1]))

[RebeccaJillianBeattie]

[federicabonifazi]

[CarmenSantaniello]

Reverse with slicing:

def test_my_reversed(input_list, expected):
    result = my_reversed(input_list)
    if expected == result:
        return True
    else:
        return False

def my_reversed(input_list):
    output_list = input_list[::-1]
    return output_list

my_list = [0, 1, 2, 3, 4, 5]

print(test_my_reversed(my_list, [5, 4, 3, 2, 1, 0]))
print(my_reversed(my_list))

It returns:

True 
[5, 4, 3, 2, 1, 0]

[11051620]

def my_reversed(input_list):

my_stack = deque()

for item in input_list:
    my_stack.appendleft(item)
    
return my_stack

[olgagolgan]

[martasoricetti]

[ManueleVeggi]

#Test code for the algorithm
def test_my_reverse(input_list, expected_reverse):
    result = my_reverse(input_list)
    if result == expected_reverse:
        return True
    else:
        return False

#Code for the algorithm
def my_reverse (input_list):
    olist = list()
    while len(input_list) > 0:
        item = input_list[-1]
        olist.append(item)
        del input_list[-1]
    return olist

#Some of the possible tests
print(test_my_reverse(["a", "b", "c", "d"], ["d", "c", "b", "a"])) # N. 1, expect: T
print(test_my_reverse(["a", "b", "c", "d"], ["d", "b", "c", "a"])) # N. 2, expect: F
print(test_my_reverse(["a", "b", "c", "d"], ["a", "b", "c", "d"])) # N. 3, expect: F
print(test_my_reverse(["a", "b", "c", "d"], ["a", "b", "c"]))        # N. 4, expect: F
print(test_my_reverse(["a", "b", "c", "d"], ["a", "a", "c", "d"])) # N. 5, expect: F

If code is run, the results coincide with our expectations: therefore the code should be correct

[tommasobattisti]

def test_my_reversed(input_list2, expected):
    result = my_reversed(input_list2)
    if result == expected:
        return True
    else:
        return False


def my_reversed(input_list2):
    output_p_list2 = []
    while len(input_list2) > 0:
        output_p_list2.append(input_list2.pop())
    return output_p_list2

print(test_my_reversed([1, 2, 3, 4, 5], [5, 4, 3, 2, 1]))
print(test_my_reversed(['a', 'b', 'c', 'd', 'e'], ['e', 'd', 'c', 'b', 'a']))

[katya-avem]

[OrsolaMBorrini]

def test_my_reversed(input_list,expected):
    my_result = my_reversed(input_list)
    if my_result == expected:
        return True
    else:
        return False

def my_reversed(input_list):
    output_list = list()
    for item in input_list:
        output_list.insert(0,item)
    return output_list

example_list = [0,1,2]
print(test_my_reversed(example_list,[2,1,0])) #This should return True
print(my_reversed(["A","B","D","K","C"]))

[chloeppd]

[MaddaGh]

[AnastasiyaSopyryaeva]

Task_5

def testing(input_list, expected):
    result = my_reversed(input_list)
    if result == expected:
        return True
    else:
        return False

def my_reversed(input_list):
    output = []
    number = 0
    maxnumber = len(input_list)
    while number < maxnumber:
        output.append(input_list.pop()) 
        number +=1
    return output

print(testing([0, 1, 2], [2, 1, 0]))
print(testing([0, 1, 2, 5, 6], [2, 1, 0]))

Returns
True
False